Meeting Abstract
Embryos of the annual killifish Austrofundulus limnaeus can live without oxygen for a matter of hours, or over 100 days, depending on their developmental age. Studying the changes in their cellular response to anoxia, and comparing these across developmental stages reveals critical components of extreme vertebrate anoxia tolerance, which may hold clues to treatment and prevention of heart attack and stroke. Recently, small non-coding RNAs (such as microRNAs) have been found to play a role in metabolic depression and cellular response to hypoxia, by altering gene expression. In this study, we examined small RNA expression profiles of A. limnaeus embryos during anoxia and aerobic recovery, at four developmental stages. We identified highly differentially expressed small RNAs at each developmental stage in response to anoxia, as well as RNAs differentially expressed between developmental stages. Some sequences of interest matched ischemia-responsive small RNAs, previously described in anoxia-sensitive mammalian models. However, many of the sequences have yet to be described. These novel sequences may provide insight into the unmatched anoxia tolerance of A. limnaeus embryos. To begin to understand how these sequences function, we visualized them within the whole embryo, using in situ hybridization (ISH). ISH studies localized sequences to the developing brain and neural tissue, some of the most anoxia-sensitive tissues. The small RNA expression profiling and whole-embryo localization are the first studies of its kind in a highly anoxia tolerant vertebrate, and provide a foundation for further inquiry. Funding: NSF IOS-1354549, NSF DGE-1057604
